On 2016-10-03 17:14, chrischris201...@gmail.com wrote:
hello
i try to follow some tutorial but i have that error :
Traceback (most recent call last):
File "C:\Python27\test\test\earth.py", line 42, in <module>
slope_array = np.ones_like(data_array) * nodataval
TypeError: unsupported operand type(s) for *: 'int' and 'NoneType'
The errors is saying that nodataval is None.
first i define that lines of code :
data_array = raster2array(filename)
nodataval = getNoDataValue(filename)
and the line with error :
slope_array = np.ones_like(data_array) * nodataval
how can i fix this error ?i change type field ?
on the four prints:
Look at what print(nodataval) shows. It says that nodataval is None.
print(resolution)
print(nodataval)
print(type(data_array))
print(data_array.shape)
i take that exports :
{'east-west': 0.0002777777777777778, 'north-south': 0.0002777777777777778}
None
<type 'numpy.ndarray'>
(3601, 3601)
the full code :
Why is nodataval None? It's because getNoDataValue returned None, which
means that band.GetNoDataValue() returned None.
You'll have to read the docs to see under what conditions it does that.
from __future__ import division
from osgeo import gdal
from matplotlib.colors import ListedColormap
from matplotlib import colors
import sys
import numpy as np
import matplotlib
import matplotlib.pyplot as plt
import math
filename = 'dem.tif'
def getResolution(rasterfn):
raster = gdal.Open(rasterfn)
geotransform = raster.GetGeoTransform()
res = {"east-west": abs(geotransform[1]),
"north-south": abs(geotransform[5])}
return res
def raster2array(rasterfn):
raster = gdal.Open(rasterfn)
band = raster.GetRasterBand(1)
return band.ReadAsArray()
def getNoDataValue(rasterfn):
raster = gdal.Open(rasterfn)
band = raster.GetRasterBand(1)
return band.GetNoDataValue()
data_array = raster2array(filename)
nodataval = getNoDataValue(filename)
resolution = getResolution(filename)
print(resolution)
print(nodataval)
print(type(data_array))
print(data_array.shape)
[snip]
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